Batman vs. Superman Billboard in I am Legend

You may have already heard about it — there is a scene early on in “I am Legend” (I’m still writing a review for it, by the way) early in the film where Will Smith is in a deserted Times Square, and as the camera slowly pans, there is a giant “Batman vs. Superman” poster/billboard staring right back at you. It looks like advertising for “Batman vs. Superman”, and since the world of “I am Legend” has remained unchanged since 2009, what are the filmmakers trying to tell us?